1. Field of the Invention
The present invention relates to a display apparatus wherein a self-luminous device such as, for example, an organic electroluminescence device (organic EL device) is used in a pixel circuit and a method for controlling a light detection operation of a light detection section provided in the pixel circuit.
2. Description of the Related Art
In a display apparatus of the active matrix type wherein an organic electroluminescence (EL: Electroluminescence) light emitting element is used as a pixel, current flowing to a light emitting element in each pixel circuit is controlled by an active device, generally a thin film transistor (TFT) provided in each pixel circuit. Since an organic EL device is a current light emitting element, a gradation of color development is obtained by controlling the amount of current flowing to the EL device.
In particular, in a pixel circuit which includes an organic EL device, current corresponding to an applied signal value voltage is supplied to the organic EL device to carry out light emission of a gradation in accordance with the signal value.
In a display apparatus which uses a self-luminous device such as a display apparatus which uses such an organic EL device as described above, it is important to cancel the dispersion in light emission luminance among pixels to eliminate non-uniformity which appears on a screen.
While the dispersion in light emission luminance among pixels appears also in an initial state upon panel fabrication, the dispersion is caused by time-dependent variation.
A light emission efficiency of an organic EL device is degraded by passage of time. In particular, even if the same current flows, the emitted light luminance degrades together with passage of time.
As a result, a screen burn that, if a white WINDOW pattern is displayed on the black background and then the white is displayed on the full screen as shown, for example, in FIG. 17A, then the luminance at the portion at which the WINDOW pattern is displayed decreases.
A countermeasure against such a situation as described above is disclosed in JP-T-2007-501953 or JP-T-2008-518263 (referred to as Patent Documents 1 and 2, respectively, hereinafter). In particular, Patent Document 1 discloses an apparatus wherein a light sensor is disposed in each pixel circuit and a detection value of the light sensor is fed back to the system to correct the emitted light luminance. Patent Document 2 discloses an apparatus wherein a detection value is fed back from a light sensor to a system to carry out correction of the emitted light luminance.